GCSE Flashcards
Why is it important to control body temperature?
so enzymes work their best
chemical reactions are at their fastest
to prevent damage to enzymes/cells
Reflex action vs action controlled by hormones
- reflex action quicker
- effect of reflex action over shorter period
- hormone involves blood system and reflex involves neurones / nerve cells
ignore nervous system / nerves - reflex involves impulses and hormone involves chemicals
- reflex action affects only one part of the body
Why can insulin not be taken as a tablet?
insulin is a hormone - which is a type of protein - which get broken down in the stomach during digestion
What are hormones?
they are chemical messengers sent in the blood produced by a gland
Describe how the mature eggs are used in IVF treatment so that the woman may become pregnant.
egg is fertilised using a male sperm
this forms an embryo
embryo inserted in woman’s uterus
Why have IVF clinics have been set a target to reduce multiple births?
multiple births lead to low birth weight
multiple births can cause harm to mother (miscarriages)
Which microscope is used for what?
- light microscope - lets us see the nuclei - lower resolution
- electron microscope - lets us see mitochondria, ribosomes, plasmids and chloroplasts - higher resolution + magnification so gives a sharper image
Why can antibiotics not treat viruses?
viruses live inside cells
Colonies of bacteria are formed through:
cell division
Repeats help to check the…
reliability
Uses of stem cells:
- medical research
- medical treatment
What happens in a red blood cell?
oxygen combines with haemoglobin
Why does glucose concentration first increase then decrease in the small intestine?
carbohydrates are broken down into sugars by amylase
What is starch a type of?
carbohydrate
What is amylase a type of?
carbohydrase (which is an enzyme)
Why does concentration of glucose in the small intestine decrease?
absorption of glucose
into the blood
by active transport
Osmosis
- The movement of water molecules from a high concentration to a low concentration through a partially permeable membrane.
- It is a passive process
What happens if cell is put into water?
water moves in
cell will swell
cell may burst
Roots absorb
water and mineral ions
If a plant loses water..
it wilts or dies
Adaptions of the lung for gas exchange:
many alveoli
short diffusion pathway (one cell thick)
large SA
good blood supply (steep concentration gradient)
Parts of a plant
- permanent vacuole contains cell sap (weak concentration of sugars + salts)
- chloroplast contain chlorophyll (green pigment) that absorbs light, and is the site of photosynthesis
- rigid cell wall - contains cellulose which strengthens and supports the cell
If it asks to circle the egg cell in a punnet square, what do you circle?
one X chromosome under the mother
If it asks to circle the sperm cell in a punnet square, what do you circle?
one Y chromosome under the father
Works of Alfred Wallace, Charles Darwin and George Mendel:
Alfred Wallace
- speciation
- noticed warning colours are used by some species (e.g. butterflies) to deter predators
Charles Darwin
- ‘Origin of Species’ - book
- natural selection/survival of the fittest
- evolution
George Mendel
- did genetic experiments on pea plants and how the characteristic of plants were passed onto their offspring
- characteristics determined by ‘hereditary units’ (now known as genes)
What is cystic fibrosis?
- inherited disorder
- causes thick sticky mucus to block airways - reduces gas exchange
- recessive
- cell membrane does not produce chloride ions efficiently
Why are the offspring in embryo transplantation not genetically identical to the mother?
due to genes from the father in the sperm - which was needed to fertilise the egg
Genetic material is made of…
DNA
Drawbacks of selective breeding:
- reduce gene pool so leads to inbreeding as breeding from the ‘best’ which are all closely related
- reduced gene pool = more health problems
- reduced gene pool = less variation = easily wiped out by disease
What did Lamarck believe?
the changes that happened to organism throughout its lifetime can be inherited by its offspring - so if a characteristic was used a lot by an organism, it would become developed, and then be passed onto the offspring
Explain why the population of black peppered moth increased and white peppered moth decreased when pollution (from sulfur dioxide) covered trees?
black moths camouflaged better so were harder to spot
so less likely to be eaten by predators
so black moths can survive and reproduce - so pass on their genes
Pyramid of biomass vs Pyramid of number
Biomass
- decreases as you go up
- is the total mass - ie 1 tree is very heavy
Number
- is the number in relation to the chain
- ie 1 tree
Control variables make results
comparable
The nucleus
contains genetic material that controls cell activity
What should be considered before taking a drug?
- cost
- side effects/allergies
- other medications being taken
- other medical conditions
How is a plant with few stomata adapted to survive hot desert conditions?
few stomata = less transpiration = less water loss
What do stomata control
- gas exchange (carbon dioxide in and oxygen out)
- water loss
Do the stomata open/close or is it the guard cells?
stomata (guard cells become turgid when the plant has lots of water as water moves into the cell - so stomata opens to allow gases in for photosynthesis)(guard cells become flaccid when the plant lacks water - so stomata close to reduce water loss)
Diffusion is the movement of
particles
The phloem transports
dissolved sugars
If there is a high concentration of water in the air then it is…
humid
At optimum temperature, enzyme + substrate have…
more KE = moving faster = more collisions = more binding = more product formed/increased rate of reaction
Why don’t we filter lipids when doing a food test?
lipids can stick to filter paper
A faster reactions means…
more product made
A faster reactions means…
more product made
Ways to reduce the negative impacts of human activity on the environment:
- breeding programmes
- regeneration
- recycling
- protect habitats
- reintroduction of field margins/hedgerows
- raising awareness with politicians/public
Ways to reduce the negative impacts of human activity on the environment:
- breeding programmes
- regeneration
- recycling
- protect habitats
- reintroduction of field margins/hedgerows
- raising awareness with politicians/public
amino acids + nitrate ions make
proteins
Uses of glucose:
- to make fats/oil - stored in seeds
- to make cellulose - to strengthen cell walls
- for respiration - for energy release
- to make starch - for storage - as it’s insoluble
- to make amino acids (with nitrate ions) - used for proteins synthesis
Why is it better to do exercise indoors when testing the affects of exercise on blood flow to organs?
constant temperature
constant speed
constant terrain
constant effort
fossil
remains of an organism
from a long time ago
An animal has a characteristic/adaptation to:
kill predators/prey
to fight for mates/territory/food
Estimate the age of the fossil by:
comparing it to fossil records/ other fossils
by using the age of the surrounding rock
Why can’t older fossils be found
older fossils were soft-bodied - so most issued decayed
fossils buried deep so hard to find
fossils destroyed by volcanoes
How is a fish fossil formed that is found in sediment?
fish dies and is buried in sediment
soft parts are decayed
mineralisation occurs and replaces bones
Process of natural selection
variation in a species due to mutation
better adapted survive
reproduce and pass on genes to offspring
Effect of increased phagocytosis on patient health:
WB cells will engulf and ingest more pathogens
which will reduce damage to cells + tissue
Clinical trials
- test the drug on cells to test for efficacy and toxicity
- test the drug on live animals for efficacy and toxicity
- If safe, test on small sample of healthy volunteers at low dosages to test for toxicity
- if safe, with no side effects, increase dosage to find optimum
- then test on a large sample of infected patients in a double blind trial
- Where one group is given a placebo and one given real drug and neither patient nor doctor knows who has which to remove bias
- Here test for efficacy
- data should be peer reviewed to remove bias
Explain how injecting monoclonal antibodies can help treat a patient suffering from a virus
MAbs bind to the virus
as the antibody is complementary to the antigen on the surface of the virus
WB cells then engulf virus
Placebos are used as a
control
Uses of monoclonal antibodies
identify blood clots
locate other hormones/molecules
diagnose/ treat some cancers
